The present invention relates to reducing emissions from diesel engines and in particular mixing hydrogen with crankcase fumes to facilitate combustion.
Diesel engines are commonly used in commercial applications such as trucks and stationary engines. These engines typically have much higher compression ratios than gasoline engines, and as a result, a substantial amount of diesel blow-by escapes past the piston rings. Unlike gasoline engines which use a simple crankcase ventilation, the diesel blow-by is generally vented to the outside, and presents a source of unpleasant fumes. The diesel engines typically can not simply vent the crankcase to the engine intake, because the diesel blow-by includes components which will degrade the diesel engine operation.
U.S. patent application Ser. No. 11/330,466 for “HYDROGEN AUGMENTED DIESEL CRANKCASE VENTILATION,” the parent of the present application, discloses a system combining hydrogen and crankcase fumes in the intake of a diesel engine, whereby the hydrogen facilitates burning the crankcase fumes to reduce emissions and to improve mileage. The system of the '466 application includes a filter 36 in the line carrying the crankcase fumes to the engine intake. In some cases, liquids included in the crankcase fumes have filled the filter and prevented optimal operation of the system. Further, many diesel engines draw air from the intake manifold which is pumped into a tank and used to actuate, for example, air brakes. Drawing hydrogen into such a system may result in undesirable conditions.